How could you really vote with your feet though?
So loads of new builds decide to go for the mixed sex option. I hate it, but don't have a lot of choice when i'm in those places, so I'll end up using it. They aren't going to record my unhappiness about it, so it'll look like a win.
Or I'll go elsehwere, and they won't know that I've gone elsewhere, because again there will be no measurements for that. They'll just look at people using the mixed sex facility and think 'great, it's working'.
Or I might not go to the place at all. This would restrict my life if it's somewhere I wanted to go but can't, or needed to go. And again, they aren't really going to know about it. OK if there are two identical coffee shops side by side and they can measure who uses the mixed sex one and who uses the one with sex segregated facilities, maybe. But in reality, no. And I'll just not end up going to place I'd like to.
And even if they do realise that people aren't liking it, they're hardly going to spend large sums to re-do the facilities at that point, especially if they aren't doing well as a business. Or if they are a council-funded place with no funding for renovations either. So again we're stuck with them.
In reality, women will just end up silently unhappy with all the mixed sex options, but not really be able to do anything about it.
And I have no desperate need to avoid mixed sex facilities really; I just don't like them. Men's facilities smell and are messy, and I'd rather not have them in mine. I prefer privacy and dignity. I don't feel particularly unsafe, but I can see that others would feel quite unsafe or triggered. So for very many reasons, I don't see why we should get rid of single sex facilities given that that is what most women are likely to prefer.
If you want to have choices, why not do a big consultation on every new building with all the likely users, and find out exactly what people prefer and why. And if mixed sex spaces are needed, then incorporate a few places in line with the proportion of people that feel they have to have them.